Ski



H. HEAD June 25, 1963 SKI 2 Sheets-Sheet'l Filed Sept. 21, 1956 H. HEAD `lune 25, 1963 SKI 2 Sheets-Sheet 2 Filed sept. 21, 1956 A PRAcT/@AL MIN/MUM l 0F HEMA/NIN@ METAL [en/EL UNB/5 VEL E0 EDGE STR/P l R m Em V mm 0 P U H of m M M L Mm mM AS v KT c 0 m0 N TR K DT mW EA H L TT ./F 0l EL ,W0 WS an mw Bgm M ,4%@494/ v ATTORNEYS United States Patent Office 3,095,207 Patented June 25, 1963 S Howard Head, 1507 Roland Heights, Baltimore 11, Md. Filed Sept. Q1, 1956, Ser. No. 611,095 2 Claims. (Cl. 280-11.13)

'which is characterized by an improved construction respecting the attachment of the continuous edges to the ski.

`Other objects and advantages of the present invention will become more readily apparent from the following description of preferred embodiments of the invention when considered with the appended 'drawings in which:

FIGURE l is a view in top plan of a ski embodying the principles `of the present invention;

FIGURE 2 is a view in section taken along line 2-2 of IFIGURE 1;

FIGURE 3 is a view in section along line 3-3 of FIGURE l;

FIGURE 4 is an enlarged detail showing a lower corner construction of the ski;

FIGURE 5 is an enlarged detail similar to FIGURE 4 showing an alternative embodiment of the present invention;

FIGURE 6 is a bottom plan view illustrating the relationship between the edge and the bottom plate;

FIGURE 7 is a view in section taken along line 7-7 of FIGURE 6;

FIGURE 8 is a view in section illustrating a new uniform shape for the strip;

FIGURE 9 is a view in section illustrating a further shape for the strip; and

FIGURE l0 is a schematic view illustrating the principles of the invention.

Referring now to the drawings in detail, a preferred embodiment `of the present invention will be described. The ski is comprised lof a top plate 10, a bottom plate 11 and core 12 arranged together in sandwich fashion. The core 12 is thickest approximately at the midpoint of the ski and tapers toward Iboth the front end and rear end lof the ski terminating short of both ends of the ski. 'Ihe core material may be made of any suitable material, but is preferably kfabricated lfrom a plurality of adhesive connected sections of edge-grain plywood. The core 12 terminates spaced from bot-h ends of the ski as mentioned and an insert `13 is positioned between the top plate and bottom plate at the rear end and an insert 14 is located between the top plate 10 and bottom plate 11 at the tip end.

'IThe two plates 10 and 1-1 and the two inserts 13` and 14 are preferably composed of an aluminum alloy. -It will be appreciated, however, that other materials, Lhaving the requisite tensile strength, elasticity and other properties, can be used instead. The bottom plate 11 of the ski may be deformed to define a groove extending axially of the ski. 'Ibis groove appears in practically all skis and its function of longitudinal stability is well appreciated. The core 12 is made in two sections, each of which extends axially relative to the ski. Also, each section is located to one side of the groove defined in bottom plate 11, off the longitudinal mid-line of the ski, as is illustrated in FIGURE 3, so that a lon- 2 -gitu-dinally extending space is [defined between the two core sections 12 and the top and bottom plates 10 and 11.

The top plate 10 is preferably provided with a protecting surface, which will impart a very pleasing appearance. There is shown a film or coating 15 applied coextensive with the upper surface of top plate 10. Although the coating 15 may be of any material, it is preferred that the coating be a phenol-formaldehyde resin, an anodic ilm, or the like.

Between the top plate 10 and the lower plate 11, along both sides of the ski, there are provided strips 16, preferably composed of a phenol-formaldehyde resin or the like although :other materials may be equally suitable. It will be noted that the width of the top plate 10 is slightly less than the width of the bottom plate 1.1, and that the lower portions of the strips 16 are somewhat enlanged as indicated lby the numeral 17. All of the parts thus .far described are bonded together using a suitable waterproof adhesive, thus the core sections 12 are bonded to the lower plate 11, the top plate 10 and the strips 16, and the coating 15 is bonded coextensively with the upper surface of the top plate 10.

A pair of slits are out or milled in the bottom plate 10, each extending from adjacent a lower corner or edge of plate 11, at an incline, toward the middle of the bottom plate 11 and terminating spaced from the top surface lof the plate 11. These slits are, in effect, marginal since they extend along either side or mangin of plate 11. These slits are cut or milled from the rear end of the plate 11 for the full length of the plate 11 or any portion of the length of the plate 11. By virtue :of the manner in which the slits are cut or milled in the plate 11, there is provided an ovenhanging portion 18 of the plate 11 forming the top lboundary of each slit and a lower lip L19, the edge of which is slightly set back as shown in FIGURE 4, which partially forms the lower boundary of each slit. Since the edge of the lower lip 19 is set back, the youter portion of each slit is open at the bottom. Strips 20 of hard material, such as steel, are placed in the slits or grooves, out or milled in the plate 11, along each side thereof. Since each slit or .groove lies at an incline, each strip 20 is received in the slit or groove at an incline. The lower corner or' edge of each strip 20 lies in or just below the plane of the bottom surface of the plate 1-1. The strips 20 are bonded in their respective slits or )grooves to the bottom plate 11.

A coating 21, to function as a running surface, is applied to the bottom surface of the plate 11. Coating 21 is preferably composed of a phenol-formaldehyde resin. Since the edge yof each lip 19 is set back, each strip 20 presents an exposed bottom face to the coating 21. By the construction described, each strip 20 is securely retained in the groove or slit cut in the plate 11, first by the lip 19 which holds the inner portion of the strip, and also by the plastic coating 21 which holds the outer portion of the strip 20.

The lower corners of the ski are finished by first being squared as indicated by the numeral 22 (see FIGURE 4). Thereafter a small portion of the coating 21 is removed to create a small groove 23 which functions to increase further the tlongitudinal stability of the ski. The squaring of the corners and the formation of the groove 23v imparts a more trim appearance to the ski. Since the strips 20 are glued in their slits it is extremely important to make the glue joint or glue line as strong as possible. It has been discovered that this glue line can be greatly strengthened, thereby restricting the possibility of glue failures due to shocks and impacts. It is preferred that a liller be utilized in the glue line between the strip 20 and the plate 11. As shown in FIGURE 4 a relatively thick glue line 24 is present at all points between plate 11 and strip 20. The presence of the filler in lthe glue line increases its strength by providing a spongy bulk which prevents stress concentrations that would accumulate in an otherwise thin glue line. It is preferred that the `fil-ler be of a fibrous nature such as cloth, sawdust or glass fiber, Vthe last named being the best.

YThe front end `of each strip 20- passes through a hole 25 dened in the plate 11 toward the tip end of the ski. For this purpose, the leading end of each strip 20 is Vtapered to a point, as indicated by the numeral 26. It will be noted that the tapering of the strip proceeds from its outer edge inwardly with the inner edge of the strip 20 being left straight. 'Ihe extreme tip 27 of the strip 20 is tucked through the hole 25 and lies on the top surface of the plate 11. This is better illustrated in FIG- URES 6 and 7 which show only relationship of the plate 11 and one strip 20. By virtue of the construction described, an improved ski results having continuous strips of hard material integrally attached along the lower corners of the ski. The attachment is achieved by inserting the strips securely in grooves or slits cut or milled in the bottom plate 11 of the ski, and bonding the strips 20 to plate 11. Cutting the slits defines recessed lip portions 19 which .actively engage the strips 20. Further a plastic coating 21 bonded to eX- posed portions of the lower faces of the strips y20 and to plate -11 further assists in retaining the strips 20 in their proper relationship to the rest of the structure. By using continuous strips 20 and vattaching them as described, they actually increase the structural strength of the ski.

In FIGURE is illustrated a further embodiment of the present invention Ywhich utilizes strips 30 much narrower than those employed in the construction described in FIGURES 1 to 4 and 6 and 7. As shown in FIGURE 5, a strip y-30y of substantially reduced width -is set into a much narrower slit or groove cut or milled into the lower plate 11. Since the strips are considerably narrower, it is possible to achieve a greater angle of incline between the plane of strip 30 and the plane of the plate V11 vwithout danger of breaking through the top surface of the plate 11. Thus, there results an overhanging portion 31 of the plate 11 and a lip portion 32 which extends nearly to the side of plate 11 and which forms the bottom boundary of the slot. The strip 30 is glued or bonded as indicated at 34 in the slit or groove and with Ythe support afforded by the portions of plate 1:1 is securely retained in position. As before a filler rin the glue line imparts greatly increased strength. -In this embodiment no additional means are required to retain the strips in their respective slits. The remainder of the construction illustrated in FIGURE 5 consists of a coating 33 formed on the bottom surface of the plate y11. The coating 33 must be hard, abrasion resistant, and provide a good running surface for the ski. It has been found that such a coating can be formed on the surface of plate 11 by anodic oxidation carried out under carefully controlled conditions. The preferred coating is achieved following the method described in U.S. -Patent Nos. 2,692,851 and 2,692,852 which disclose in detail all necessary instructions to produce a hard, abrasion-resistant aluminum oxide anodic coating.

Like the showing of FIGURES 1 to 4 the ski of FIG- URE 5 is finished by squaring its corners and removing material to form a minute groove 35 along each side.

The design of the present invention possesses distinct advantages over conventional Vdesigns heretofore employed, especially with reference to the attachment or installation of the steel strips or edges. In conventional designs, the steel strips are attached along the edges of the bottom surfaceY of the ski, the attachment being effected by means of adhesives or screws. In such a design, the only factor tending to restrainthe edge or strip or prevent spreading of a failure is the bending stiffness of the steel edge or strip. This bending stiffness is quite slight.

When the inner edge of the steel strip, however, is retained `or received in a narrow slit or slot, such as defined in the lower or bottom plate 11 y(see FIGURES l to 4), a second lfactor comes into play. When the primary bond (the adhesive) is broken by a blow `or shock, the steel strip now must rotate locally, since the lip 19 functions as a hinge. Accordingly, the construction forces a torsion effect. Hence, the torsion stiffness of the steel strip or edge also comes into play tending to restrain a failure from spreading further. The torsional rigidity `of a steel strip or edge as employed in -the present invention is larger by a factor of approximately 10 than the simple Vbending effect noted above.

When the steel strip or edge is placed into a relatively deep slit Vor slot as illustrated in FIGURE 5, and the ratio of strength of lip 32 to width of the strip 30 is properly chosen, then, still a third factor enters into restraint of the strip 30. The large lip 32 contributes its own Ibend- Yin-g strength in addition to acting or functioning as a hinge, further supplementing the strength and effectiveness of the construction. Accordingly, in the embodiment of the invention as illustrated in FIGURE 5, 4there are three factors tending to maintain the edge or strip in its proper relationship to .the ski and to prevent spreading of any failure. These factors are, namely, that the edge, or strip itself must bend, that since the strip is received in a slit -or slot it must, as a whole,v twist, and if the metal lip (lip 32) is large and strong in proportion to the width of the strip or edge then lip 32 exerts a bending strength acting against displacement of the strip. For the last named factor to be fully effected, it is required that the thickness of the lip 32 at its root be approximately equal to the thickness of the strip 30 and that the total width of the lip 32 be at least 50% of the width of the strip 30.

It twill be understood that the configuration of the marginal slits, as well as their relationship vto the plate 11, can be varied within wide limits. In FIGURES 8 and 9 there are illustrated possible variations. In IFIGURE 8 the slit is shown as being irregular and as receiving a complementary shaped strip 50. The advantage of the lconfiguration of FIGURE 8 is that the strip 50 can lbe substantially thicker. In FIGURE 9 the slit is cut or milled substantially parallel to surfaces of plate 11 and the received strip 51 is provided with a depending portion 52. The point is, the slit can be of any shape whatsoever whether regula-r or irregular. The lower lip of the slot can be of any length depending upon thecharacteristics desired as previously described. Thus it can be very short or quite long. I f the slot is inclined it must lie at an angle of less than about 20 with respect to the plane of .plate 1,1. Preferably the angle should be less than 13 and in the range of from 8 to 13.

FIGURE 10 illustrates the principles of the invention. As shown, a layer of parent metal, in this case aluminum, is provided with a slit. The object of the construction is to attain a lip having the greatest possible root thickness taking into account all-other considerations. Since the slit is cut at an angle there must be retained a practical minimum of parent metal. 'Ihis is indicated at A. 'I'he slit itself also has depth or thickness in a vertical direction even though on an incline. Thus, the projected thickness of the slit at its root or in other words, the vertical component or dimension of the slit becomes a consideration in arriving at the maximum root thickness for the lip. If the slit were rectangular it would have to be quite narrow. It is possible, however, to bevel the upper end of the slit and thereby achieve two ends, namely, to reduce greatly the projected thickness of the root of the slit and at the same time enable a slit to be cut which is substantially wider. The design of FIGURE 8 structurally illustrates the advantages of the principles illustrated in FIGURE l0. As will be apparent in FIG- URE 8 a wider strip 5G is possible with the maximum root thickness for the lip.

Although the present invention has been shown and described With reference to specific embodiments, nevertheless, various changes and modifications obvious to one skilled in the art are Within the spi-rit, scope and contemplation of the invention.

What is claimed is:

1. In a laminated ski including an upper plate and a lower metallic plate having a core material disposed therebetween, the improvement that comprises a marginal slit having at least three planar surfaces defined along each side of the lower plate, -a steel strip at least partially received in each of said slits, said strip having at least one at transverse surface, the dat transverse surfaces of the respective strips -being disposed at an angle of less than 20 to the plane of the lower plate, the portion of said lower plate forming the lower boundary of each of said slits defining a supporting lip to support the strip against movement relative to the remainder of the ski, said strip being secured to said lower plate, the llowermost transverse surface of said strip dening with the extreme end of said lip a notch extending longitudinally of the ski along the bottom thereof.

2. A laminated ski as defined in claim 1 wherein each of said supporting lips is at least half as wide as one of said strips.

References Cited in the le of this patent UNITED STATES PATENTS 2,377,504 Lermont June 5, 1945 2,446,591 Hoerle Aug. 10, 1948 2,692,851 Burrows Oct. 26, 1954 2,692,852 Burrows Oct. 26, 1954 2,694,580 Head Nov. 16, 1954 2,743,113 Griggs Apr. 24, 1956 FOREIGN PATENTS 184,498 Aust-ria a Jan. 25, 1956 979,589 France Dec. 13, 1950 

1. IN A LAMINATED SKI INCLUDING AN UPPER PLATE AND A LOWER METALLIC PLATE HAVING A CORE MATERIAL DISPOSED THEREBETWEEN, THE IMPROVEMENT THAT COMPRISES A MARGINAL SLIT HAVING AT LEAST THREE PLANAR SURFACES DEFINED ALONG EACH SIDE OF THE LOWER PLATE, A STEEL STRIP AT LEAST PARTIALLY RECEIVED IN EACH OF SAID SLITS, SAID STRIP HAVING AT LEAST ONE FLAT TRANSVERSE SURFACE, THE FLAT TRANSVERSE SURFACES OF THE RESPECTIVE STRIPS BEING DISPOSED AT AN ANGLE OF LESS THAN 20* TO THE PLANE OF THE LOWER PLATE, THE PORTION OF SAID LOWER PLATE FORMING THE LOWER BOUNDARY OF EACH OF SAID SLITS DEFINING A SUPPORTING LIP TO SUPPORT THE STRIP AGAINST MOVEMENT RELATIVE TO THE REMAINDER OF THE SKI, SAID STRIP BEING SECURED TO SAID LOWER PLATE, THE LOWERMOST TRANSVERSE SURFACE OF SAID STRIP DEFINING WITH THE EXTREME END OF SAID LIP A NOTCH EXTENDING LONGITUDINALLY OF THE SKI ALONG THE BOTTOM THEREOF. 